Heretofore, as the liquid crystal display device employing electrooptical effect, there have been developed many devices using a cell such as a DSM cell employing dynamic scattering effect, guest-host cell using a coloring matter, TN cell having a twisted nematic structure, SBE (Super-Twisted Birefringence Effect) cell, and STN (Super-Twisted Nematic) cell. Among these, most generally used liquid crystal display devices are based on Schadt, Helfrich effect using a nematic liquid crystal exhibiting positive dielectric anisotropy, and the liquid crystal has a twisted nematic structure. Recently, OCB (Optically Compensated Bend) cells having a wide viewing angle have been proposed as a mode which is close to practical use (Miyashita et al., Euro-Display '93 Digest, pp 149-152).
As display devices which use a liquid crystal material having negative dielectric anisotropy, ECB (Electrically Controlled Birefringence) type liquid crystal display devices employing electrically controlled birefringence effect are generally known. The devices are to employ the change in light transmission by effectively varying birefringence due to the deformation of a nematic layer having a negative dielectric anisotropy, in an electric field. The mode in which a new orientation control is added to the ECB mode and an optical compensation plate is used is a SH (Super-Homeotropic: Yamauchi et al., SID '89 Digest, pp 378-381) mode.
In these modes, display devices which use a liquid crystal material having positive dielectric anisotropy have a narrow viewing angle and an insufficient response speed. Also, ECB type liquid crystal display devices which employ negative dielectric anisotropy have such problems that response is slow, that steepness is poor, and that threshold voltage is high.